Nail guns are powered devices that project a nail through the tip of the nail gun into an external structure. Most nail guns are powered through compressed air, but nail guns can also be electrically driven. The nail gun holds a supply of nails in a magazine to be presented one at a time in a chamber to be driven from the chamber into the external structure. In the configuration schematically depicted in FIG. 1, the nail gun 1 has a supply of nails 2 arranged in an array in the magazine 3 with the endmost nail 2 positioned in the chamber 4. A piston 5, powered by compressed air connected to the compressed air port 6 of the nail gun 1 when the trigger 7 is pulled, drives the nail 2 out of the chamber into the structure that is positioned adjacent the tip 8 of the nail gun 1. After driving the nail 2 from the chamber 4, the piston 5 returns to the retracted position and the spring-loaded magazine pushes the next nail 2 into the chamber 4 to repeat the process.
In the way of examples, the nail gun can be used effectively to nail shingles to the outer surface of a roof on a building or to nail plywood to the frame structure of the building, whether that is the roof or an exterior wall. The nail gun provides an effective and efficient manner in which two members can be joined together with nails driven at a high rate of speed from the tip of the nail gun. However, the tip of the nail gun needs to be positioned adjacent one of the external members to be joined together to control the movement of the nail as the nail leaves the tip of the nail gun. Accordingly, there are some situations in the building trades where the nail gun cannot be effectively used, primarily because the tip of the nail gun cannot be positioned at the appropriate location for the application of the nail into the structure.
The attachment of siding, such as vinyl siding, to the exterior of a building structure is one such situation where the nail gun has not been used effectively. Vinyl siding 9, as schematically depicted in FIG. 1, has a connective structure 9a along the top edge of the siding panel 9 that is configured to engage with the mating connective structure 9b at the bottom edge of the siding panel 9. To attach siding 9 to the underlying exterior wall 9c of a building structure, each siding panel 9 is connected to the siding panel 9 below by interengaging the connective structures 9a, 9b and then nailing the upper edge of the siding panel 9 to the underlying exterior wall 9c. The space provided within the upper connective structure 9a along the upper edge of the siding panel 9 is too small and non-cooperatively positioned to position the tip 8 of the nail gun 1 into the space for the application of a nail from the nail gun 1. Accordingly, the conventional manner in which vinyl siding 9 is placed on an exterior wall 9c of a building is to manually nail the siding panels 9 to the exterior wall 9c. 
Nail gun configurations vary from one manufacturer to another, but all operate on the same general principle of having a magazine filled with nails to deliver a nail to a driving tool which when activated powers the nail out of the nail gun into the underlying, adjacent structure. One nail gun configuration is shown in U.S. Pat. No. 3,542,273, issued on Nov. 24, 1970, to Granville R. Hedrick, in which the nail gun is actuated by striking an impact blow to the end of the nail gun. The nail gun shown in U.S. Pat. No. 5,649,661, issued to Takayuki Masuno Kazuhiko on Jul. 22, 1997, is a more conventional nail gun powered by compressed air, but having a detachable contact foot mounted on the tip of the nail gun. In U.S. Pat. No. 8,695,860, issued to Jing-Li Wang, et al., a nail guiding structure forms a part of the nail gun structure to improve the performance thereof to deliver nails to underlying, adjacent structure.
Adaptors for use with nail guns to accomplish certain functions are known in the art, as can be found in U.S. Pat. No. 6,776,322, granted on Aug. 17, 2004, and in U.S. Pat. No. 7,066,371, granted on Jun. 27, 2006, both to Edward C. Villela, et al. In the Villela patents, the depth control spacer is placed on the tip of the nail gun to control the depth of penetration of the discharged nails into the structure adjacent thereto. The Villela depth control spacer is operable for use in to two or more layers of roofing material which contain a layer of compressible fibrous material wherein the depth control spacer prevents the fibrous layer from being permanently compressed. Another depth control adaptor is shown in U.S. Pat. No. 5,743,455, granted on Apr. 28, 1998, to Brett Holliday. An adaptor is disclosed in U.S. Pat. No. 6,880,741, issued on Apr. 19, 2005, to Donald C. Gill to facilitate the use of the nail gun having a cylindrical magazine in the nailing of replacement shingles on a building roof.
The adaptor disclosed in U.S. Pat. No. 6,393,711, issued on May 28, 2002, to Todd Freund is intended to facilitate the use of the nail gun to nail siding panels on the exterior wall of a building structure. The Freund adaptor is detachably mounted on the frame of the nail gun and is elongated to cover the discharge tip of the nail gun. The Freund adaptor has an oval-shaped opening to permit the passage of the discharged nail from the nail gun tip through the adaptor, and has an elongated guide member that sits along an upper lip of the siding panel so that the nail is discharged into the siding panel at the same height from the lip each time the nail gun is actuated.
The Freund adaptor does nothing to locate the discharge point of the adaptor or the tip of the nail gun closer to the point of insertion of the nail into the siding panel. Accordingly, the Freund adaptor suffers from the same problems associated with the use of nail guns to fasten siding panels in that the depth control of the inserted nail cannot be satisfactorily controlled. All the Freund adaptor accomplishes is to consistently position the discharge point of the nail gun at a selected height above the upper lip of the siding panel on which the elongated guide member is positioned.
It would be desirable to provide an improved adaptor for use with a nail gun that will permit the nail gun to be utilized in a consistent manner for the nailing of vinyl siding to the exterior wall of a building structure.